The Learning Early about Peanut Allergy (LEAP) study included infants aged 4-11 months at high risk of peanut allergy, who were randomised to receive peanut products (consumption group) or to avoid them (avoidance group). It was designed to examine two groups – those with evidence of pre-existing sensitivity (positive results on a skin-prick test) and those without. Those who developed a wheal >4mm in response to the skin-prick test (around 10%) were excluded due to concerns that they would have severe reactions.
For the primary endpoint of peanut allergy at 5 years of age (based on the results of a peanut challenge), there were clear differences between the two strategies. Early consumption of peanut products appeared to dramatically decrease the risk of development of peanut allergy in both those with and without evidence of pre-existing sensitivity, in this high-risk group of infants.
According to the authors of a related editorial, several questions remain unanswered. For example what amount of peanut protein is needed and does this need to be regular or intermittent; if regular consumption is interrupted then will tolerance persist; can this be applied to other foods? Although these need to be addressed, they believe that new guidelines will be forthcoming very soon, as the results of this research are “so compelling” and “make it clear that we can do something now to reverse the increasing prevalence of peanut allergy”.